In the field of nuclear medicine, it is common to utilize radioactive gases such as xenon for conducting ventilation studies upon a patient. Generally, the xenon is administered to the patient by devices adapted to dispense the radioactive gas from a sealed vial containing this gas. These vials are contained within a radioactive shield to prevent comtamination of the atmosphere with the radioactive gas. Among the devices for dispensing radioactive gas are the dispensing devices disclosed in U.S. Pat. No. 3,848,773--Adler and U.S. Pat. No. 4,192,438--Foster et al. These devices utilize needles for piercing the septum of the vial containing the radioactive gas. One of the needles is utilized to feed the radioactive gas out of the vial to the patient while the other needle is utilized to inject a displacement gas such as air into the vial to force its radioactive contents outward. In carrying out this operation, the radioactive gas in the dispenser is generally sealed from the atmosphere so that the operation of dispensing the gas from the vial takes place without leakage.
One of the disadvantages of these devices is that after the radioactive gas from the vial is dispensed, the vial must be removed from the dispenser by hand in order to dislodge the needle from the septum. This action, which is carried out by hand, may subject the user to repeated exposure to radioactive gas. As is generally known, the administration of radioactive material to a patient should be carried out with as little handling as possible in order to avoid exposing the technician to the effects of radiation.